Scaffold couplings



June 23, 1970 J. G. L owE 3,516,695

SCAFFOLD COUPLINGS Filed March 4., 1968 2 Sheets-Sheet 1 June 23, 1970J. G. Lowe: 3,516,695

scAFFoLD coul-#muss Filed March 4. 1968 I 2 sheets-show :.1

United States Patent O U.S. Cl. 287--54 3 Claims ABSTRACT OF THEDISCLOSURE A scaffold coupling for securing a non-vertical, e.g.horizontal scaffold tube to a vertical scaffold tube, with the body ofthe coupling having a downwardly directed sharp edge which deforms andlocks into the surface metal of the vertical scaffold tube, to lock thecoupling against downward movement on the vertical tube.

BACKGROUND OF THE INVENTION Field of the invention This inventionrelates to scaffold couplings for securing a non-vertical, e.g.horizontal scaffold tube to a vertical or substantially verticalsupporting tube, e.g. an upright tube of a scaffolding structure, whichcoupling is of the kind, herein called the kind specified, comprising acentral body having two oppositely directed concavedly curved seatingsand a pair of curved clamping jaws, each connected at opposite ends tothe central body, each jaw coacting with one of the two seatings inclamping one of the two tubes to be connected.

One of the most common arrangements in couplings of the kind specifiedis that in which the two seatings are mutually perpendicular so as tosecure the two tubes at right angles to one another and in such anarrangement the central body is formed as a one piece member, forexample as a forging.

Description of the prior art In couplings of the kind specified,reliance is placed wholly on the frictional engagement betwen thecoupling 'and the vertical or substantially vertical supporting tube intransmitting thereto the weight of the load transmitted from thehorizontal or other non-vertical tube to be supported, and this imposesa relatively low limit on the weight which can safely be supported bythe coupling without the serious danger that the coupling may slip downthe vertical or substantially vertical tube.

For instance in the case of a standard 2 diameter upright tube, themaximum permissible loading of a coupler having a one piece body forsupporting a horizontal tube is at present about 650 kilos.

The present invention has for its object the provision of an improvedform of scaffold coupling of the kind specified, in which asubstantially greater load can be supported through a given size ofcoupling from the vertical or substantially vertical tube, without riskof the coupling slipping down the tube.

SUMMARY OF THE INVENTION According to the present invention, the centralbody adjacent at least one of the two seatings, namely that which insitu is in clamping engagement with the vertical or substantiallyvertical tube, is formed at the in situ lower side of the vertical tubeengaging seating with a sharp downward-ly presented edge which in situis disposed below the lower edge of the jaw clamping said vertical tube,said edge being in or intersecting with a plane containing the axis ofthe vertical tube, which plane also passes 3,516,695 Patented June 23,1970 Mice through the medial part of the central body, the arrangementbeing such that with increase in the loading of the horizontal or othersupported tube the coupling rocks very slightly relative to the verticaltube in a direction such that the sharp edge can deform slightly thesurface metal of the vertical tube to engage positively therewith, andthus provide a positive engagement in addition to a frictionalengagement with the vertical tube.

Preferably, the sharp edge is constituted by a sharp corner of concaveconguration, which engages along its length with the adjacent side ofthe vertical tube, and extends in a direction perpendicular to thelength of the tube.

Preferably, the sharp edge is constituted by a part of the adjacentseating, so as to form a local extension of the seating.

Advantageously, the sharp edge is constituted by an adjacent portion ofa clamping jaw securing lug.

The invention may be applied to the particular form of scaiold couplingwhich is the subject of our prior patent application No. 688,602, tiledDec. `6, 1967.

BRIEF DESCRIPTION OF 'II-IE DRAWINGS One embodiment of the presentinvention as so applied is illustrated in the accompanying drawings,wherein:

FIG. 1 is a side elevation of one form of scaffold coupling embodyingthe invention, one of the jaws being depicted in the closed position andthe other in the open position.

FIG. 2 is a plan view of the central body of the coupling depicted inFIG. 1.

FIG. 3 is a cross sectional view of the coupler depicted in FIG. 1,shown in its nal clamping position.

Referring to the drawings, the coupling scaffold there illustrated isadapted to secure a horizontal tube 7 to a vertical scaffold tube 8, andcomprises a central body 9 of generally circular configurationperipherally, and embodying on each of its two sides two mutuallyperpendicular concave circular seatings 10, 11.

The circular periphery of the body has integrally formed therewith, twopairs of lugs 12, 13, 14, 15, one of the two lugs 12, 14 in each pairbeing of generally rectangular form in cross section, with the otherlugs 13, 15\ of each pair being formed on one side with a shallowpart-circular bearing recess 16, which provides a bearing for thecircular section head 17 of a T-shape clamping bolt 18, which '.head 17has a diameter more than twice the depth of the recess 16, so that onlya minor portion of the bolt head is received within the recess and theassociated lug 13, 15 is made of depth suicient merely to provide thisrecess 16 of the above shallow depth.

Each recessed lug 13, 15 is formed with an elongated hole 19 throughwhich the clamping bolt 17 passes, the free end portion of the clampingbolt carrying a nut 20 for engaging with the free end portion 21 ofarcuate shaped jaw 22, 23, the other end 24 of which is hinged lln/ iin25, one to each of the rectangular section lugs The said hinged end 24of each jaw 22, 23, is forked so that the two arms 26 of the fork extendon opposite sides of the lug 12, 14, and the free end 27 of each lug 12,14 is adapted as shown in FIG. l to engage with the metal of the jaw atposition 28 between the inner ends of the two arms 26 to limit theopening movement of each jaw. This latter feature is of practicalimportance in that with one half of the coupling secured rst, as iscustomary for the vertically extending or upright tube 8, the jaw of theother half of the coupling can be supported by the provision of thislast mentioned feature in a substantially horizontal position to providea rest for a horizontal tube 7 before this is finally clamped by suchjaw in position.

The central body 9 is formed integrally during the forging operationwith two pairs of lug reinforcing portions 12a, 13a, 14a, 15a, eachextending from the central body in the direction of and adjacent to thetwo pairs of lugs 12, 13, 14, 15, respectively.

Each pair of reinforcing portions 12a, 13a, adjacent to the one pair oflugs 12, 13, constitute tulbe engaging extensions of seating 10, whichcoacts with the jaw 22 secured by means of the other pair of lugs 14,15, while reinforcing portions 14a, 15a, adjacent to the pair of lugs14, 15, constitute tube engaging extensions of seating 11, which coactswith the jaw 23 secured by means of the pair of lugs 12, 13.

One of the reinforcing portions in each pair, namely 12a, 14a, which areadjacent each jaw hinging lug 12, 14, are formed at the side of theadjacent seating 10, 11, respectively with an outer sharp edge or comer12b, 1417, of sharp right angle conugration in cross section, and ofsubstantially straight configuration as viewed in FIG. 2, but curvedabout the axis of ourvature of the adjacent seating, so as to engagewith the vertical scaffold tube 8 engaged by such seating.

Thus, as shown in FIG. 3, in utilising the coupler to secure ahorizontal tube 7 to an upright tube 8, the coupler would in accordancewith normal practice be clamped first to the upright tube 8 by engagingseating 10 and corresponding jaw 22 in clamping engagement with theupright tube with the coupler in a position in which the other jaw 23for securing the horizontal tube 7 is, as is customary, in a positionfor supporting the horizontal tube in a position ready for clamping.With the parts so disposed, the said edge 12b of reinforcing portion 12in engagement with `upright turbe 8, is directed downwardly of the tube.

Thus, when the horizontal tube7 is secured and loaded, the weight whichis applied to the coupling 9 at a position to the side of upright tube 8nearest to tube 7 will cause the coupling to rock very slightly relativeto tube 8, in a clockwise direction as viewed in FIG. 3, causing edge12b to bite slightly into the adjacent surface metal of tube `8 and thusprovide a positive grip in addition to a friction grip between thecoupling and tube 8, whereby a substantially greater load can. besupported without risk of the coupling slipping down the upright tube 8.

It is believed that where the upright tube 8 is of the customary cm.external diameter, the load which can safely be carried 'by theillustrated coupler without danger of slip, can |be increased from thepresent gure of about 650 kilos to about 800 kilos.

What I claim is:

1. A scaffold coupling for securing a horizontal cy.- lindrical tube toa vertical supporting cylindrical tube,

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comprising a one-piece rigid central body which extends between the twotubes, with opposite sides of the onepiece body forming two oppositelydirected mutually perpendicular concavedly curved part-cylindricalseatings, each of curvature corresponding to that of the peripheries oftheir respective tubes, and a pair of clamping jaws, each connected atopposite ends to the central body, each jaw coacting with one of the twoseatings in clamping one of the two tubes to be connected, the lower endof that part-cylindrical seating which in situ is in clamping engagementwith the vertical tube forming a sharp downwardly presented yerticaltube engaging edge which intersects with a vertical plane passingthrough the medial part of the central ybody and containing the axis ofcurvature of the vertical tube seating, said edge in situ being disposedat a horizontal level which is below that of the underside of thevertical tube jaw and spaced below the horizontal median plane throughsaid latter jaw by a distance which is less than the distance asmeasured in said vertical plane between the axis of curvature of thehorizontal tube and the vertical tube seating, the arrangement beingsuch that with increase in the loading of the horizontal tube thecoupling rocks very slightly relative to the vertical tube in adirection such that the sharp edge can deforrn slightly the surfacemetal of the vertical tube to engage positively therewith, and thusprovide a positive engagement in addition to a frictional engagementwith the vertical tube.

2. A scaffold coupling according to claim 1, characterised in that thesharp edge is constituted by a right angle corner of concaveconfiguration, one face of which engages with the adjacent side of thevertical tube, and the other face of which extends in a directionperpendicular to the length of the tube.

3. A scaffold coupling according to claim 1, characterised in that thesharp edge is constituted by an adjacent portion of a clamping jawsecuring lug.

References Cited UNITED STATES PATENTS 788,786' 5/1905 Meyer. 2,876,0273/ 1959* Sulmonetti.

FOREIGN PATENTS 1,071,335 3/1954 France.

v804,038 11/ 1958 Great Britain. 612,058 11/ 1960 Italy.

DAVID I. WILLIAMOWSKY, Primary Examiner A. KUNDRAT, Assistant Examiner

